Electromechanical surgical system including linearly driven instrument roll

ABSTRACT

A surgical system includes a drive unit on a support. The drive unit includes motors or other actuators and a plurality of output elements arranged such that operation of each drive unit linearly translates a corresponding one of the output elements. A surgical device has an input subsystem carried at the proximal end of the shaft. The input subsystem includes linearly translatable input elements or pistons. The input and output elements are positioned such that operation of an actuator linearly translates an output element, causing linear translation of a corresponding input element. The input elements deliver linear motion to a rotary conversion system which converts the linear motion to rotary motion and delivers the rotary motion to a shaft of the surgical device, causing axial rolling of the surgical device or its distal end effector. A sterile drape is positionable between the input elements and the output elements.

This application is a continuation of U.S. Ser. No. 16/160,960, filedOct. 15, 2018, which is a continuation of PCT/US2017/27818, filed Apr.14, 2017, which claims the benefit of U.S. Provisional Application Nos.62/322,529, 62/322,539, and 62/322,585, each of which was filed Apr. 14,2016. The above applications are each incorporated herein by reference.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to the field of surgical systems usingelectromechanical drivers to effect movement of medical instrumentswithin a body cavity.

BACKGROUND

Surgical systems used for robotically-assisted surgery or roboticsurgery employ electromechanical drivers to drive movement of surgicaldevices within a body cavity, typically in response to signals generatedwhen a user moves a user input device. The surgical devices may besurgical instruments having end effectors, and/or they may be steerablelumen devices adapted to receive such surgical instruments (or acombination of such surgical instruments and lumen devices). Thesurgical devices include actuation elements (e.g. wires, rods or cables)that, when pushed and/or pulled, cause active bending or articulation atthe distal end of the surgical device, which is disposed within apatient's body. Motion produced by the electromechanical drivers is usedto push and/or pull the actuation elements to produce this bending orarticulation.

In such systems, it is desirable to avoid the need to sterilizecomponents housing motors and electronics. Instead, prior art surgicalsystems provide the driver (which houses the motors and someelectronics) as a component that may be covered with a sterile drape inthe surgical procedure room. The surgical device that is to be driven bythe driver is a separate, sterile, component removably mounted to thedriver in a manner that allows the sterile drape to maintain a sterilebarrier between the driver and the surgical device. Features areprovided for transferring the mechanical output of the motors in thedriver to the actuation elements in the surgical device, so thatactuation of the motors causes the desired movement of the distal partof the surgical device within the patient's body cavity.

In many prior art systems, the mechanical output features of the drivertake the form of rotating output elements such as shafts, disks or otherelements which rotate when the motors in the driver are energized. Eachsuch output element is rotationally coupled to a corresponding rotatableinput elements on the surgical device that, when rotated, causes thepushing or pulling of the surgical device's actuation elements. Tomaintain the sterile boundary provided by the surgical drape that isdisposed between the driver and the surgical device, the rotationalmotion from each rotating output element is transferred to itscorresponding rotatable input element using intermediate sterilerotating pieces (e.g. rotating disks) that receive the rotational motionfrom the output elements of the driver and transfer the rotationalmotion to the input elements of the surgical device.

Commonly owned, co-pending Application PCT/US15/55098 (the '098application), filed Oct. 12, 2015, publication WO 2016/057989, which isincorporated by reference, describes a surgical system that overcomesthe challenges of the prior art systems. That application describes asystem that includes a drive unit on a support. The drive unit includesmotors or other actuators and a plurality of output elements arrangedsuch that operation of each drive unit linearly translates acorresponding one of the output elements. A surgical device hasactuation elements extending through an elongate shaft to a distalarticulation section, and an input subsystem carried at the proximal endof the shaft. Linear translatable input elements or pistons of the inputsubsystem are each associated with a corresponding one of the actuationelements. The input and output elements are positioned such thatoperation of an actuator linearly translates an output element, causinglinear translation of a corresponding input element and engagement of anactuation element. A sterile drape is positionable between the inputelements and the output elements. The described system thus allows useof a sterile drape without the requirement of special adapters fortransferring motion. Input devices operable by the surgeon allow asurgeon to provide input to the system for the purpose of driving themotors to move the surgical devices.

Robotic surgical procedures can be enhanced by the addition of rollcapability to one or more of the surgical instruments, allowing the endeffector to be rotated relative to the longitudinal axis of theinstrument shaft, either by axially rolling the shaft of the instrument(with the tip thereon) or by rolling the tip of the instrument relativeto the shaft (such as by rolling an internally routed shaft on which thetip is carried). The present application describes mechanisms forachieving instrument roll using a linear mechanical input, such as thatprovided using the linear drive system of the type described in the '098application.

This application describes a robotic system (suitable for use insurgery) that provides an array of linear actuators against which anytype of surgical or non-surgical instrument could be attached andelectromechanically driven using linear inputs aligned with one or moreof the linear actuators.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first embodiment of a surgical deviceand motor drive assembly, showing the surgical device and motor driveseparated from one another.

FIG. 2 is a perspective view of the surgical device of FIG. 1.

FIG. 3A shows the motor drive and instrument of FIG. 1 positioned withthe input and output elements in the driving relationship and with themotor drive supported by a housing that can be supported by a supportarm.

FIG. 3B shows the housing of FIG. 3A mounted to an arm, with four motordrives and four surgical devices disposed in the housing.

FIG. 4A is similar to FIG. 1, but shows a portion of the motor drivehousing removed to show the presence of motors inside.

FIG. 4B shows a motor and lead screw drive associated with an outputelement.

FIG. 5 shows a proximal part of a surgical device, with a portion of thehousing removed to expose part of the subsystem.

FIG. 6 shows an actuation element and input element system.

FIG. 7 schematically illustrates a drive train assembly, including asurgical device subsystem.

FIG. 8 is a perspective view of a proximal part of a surgical device.

FIG. 9 shows the proximal portion of the surgical device, with a portionof the housing removed to allow the subsystem to be viewed.

FIGS. 10-14 are partially disassembled views of the proximal end of thesurgical device.

FIGS. 15A and 15B are perspective views of the rotary component of theconversion assembly.

FIG. 16 is a perspective view of a modified version the conversionassembly.

FIG. 17 is a partially exploded view of the assembly of FIG. 16.

FIG. 18 shows output elements engaged with input elements of analternative linear to rotary conversion assembly.

FIG. 19 graphically depicts motion of the input elements of the assemblyof FIG. 18 over time.

FIGS. 20A-20F are a sequence of drawings illustrating motion of a priorart rack and pinion assembly.

FIGS. 21A-21D are a sequence of drawings illustrating motion of amodified rack and pinion assembly suitable for use as a linear-to-rotaryand or rotary-to-linear conversion assembly.

FIGS. 22A and 22B are exploded views of the assembly of FIGS. 21A-21D.

FIG. 23A and 23B are a perspective view and a top plan view of aconversion assembly implementing rack and pinion assemblies of the typeshown in FIG. 22A.

FIGS. 24A-24F is a sequence of images illustrating the action of thepistons of the assembly of FIG. 23A in response to rotation of anassociated shaft.

FIGS. 25A and 25B illustrate an arrangement of two FIG. 23A assemblies.

FIGS. 26A and 26B are perspective views showing an assembly of racks andpinions that is an alternative to that shown in FIG. 23A.

FIGS. 27 and 28 show alternate embodiments of conversion assemblies.

FIG. 29 graphically depicts movement of the three output drive elementsof the third embodiment over time.

FIG. 30 is an enlarged view of a portion of FIG. 29.

FIGS. 31A through 31C are perspective views of various configurations ofdrive assemblies.

FIGS. 32A through 32E schematically illustrate arrays of drive pins fora drive assembly.

FIG. 33A illustrates an assembly of a drive assembly, surgical device,and auxiliary device.

FIG. 33B is a rear elevation view of the auxiliary device shown in FIG.33A.

FIG. 34 illustrates a second embodiment of an assembly of a driveassembly, surgical device, and auxiliary device.

DESCRIPTION

Referring to FIG. 1, an exemplary assembly 10 includes a surgical device12 and a drive assembly such as a motor drive 14. The surgical device 12is designed to be inserted through an incision (either directly orthrough a trocar or overtube) and positioned within a patient's body foruse in performing surgery. It may be a surgical instrument having an endeffector 23 a (See FIG. 2), or it may be a steerable lumen deviceadapted to removably receive such surgical instruments. In some cases,there is a first surgical device in the form of a steerable lumen devicedriven using the disclosed principles, as well as a second surgicaldevice in the form of a surgical instrument that is insertable throughthe lumen and that may also be steered, articulated, and/or actuated(e.g. jaw opening and closing) using the disclosed principles. In thepresent application, the illustrated embodiments show the surgicaldevice as being a surgical instrument. Exemplary surgical devices in theform of lumen devices are found in the '098 application which isincorporated by reference. The surgical device includes actuationelements that, when pushed and/or pulled, cause active bending and/orarticulation at the distal portion of the surgical device within thepatient's body. The actuation elements extend through the shaft and arepositioned to cause active bending/straightening of correspondingactively bendable sections, or articulation at joints or pivots, as thetension on the actuation elements is varied. The actuation elements areelongate elements (e.g. wires, rods, cables, threads, filaments etc)having distal portions anchored to the shaft and proximal portionscoupled to actuation mechanisms that vary the forces (tension orcompression) on the actuation elements or the positions of the actuationelements. The actuation elements generally extend between proximal anddistal directions.

Other types of actuation elements may be used (e.g. rotatable elements,inflatable elements), and the actuation elements may be used for typesof motion other than bending or articulation (e.g. rotation, open/closeof jaws or other elements, linear translation).

In the embodiment depicted in the drawings, the surgical device 12includes an elongate shaft 16 having a rigid proximal portion. Towardsits distal end there are one or more actively bendable or “steerable”sections 18 a that bend in response to movement of the actuationelements, and/or a deployment section 18 b that will articulate or bendto position the steerable section 18 a laterally away from thelongitudinal axis of the elongate shaft 16. The deployment section isuseful during positioning of the surgical devices within the body cavityto allow for triangulation of multiple instruments towards a commonoperative site. It should be understood that the term “deployment” isnot intended to convey that this section may only be used duringdeployment of the surgical device within the body. The deploymentsection may be comprised of one or more joints that articulate inresponse to movement of corresponding actuation elements, or it may beactively bendable rather than articulating. The illustrated embodimentincludes both a steerable section 18 a that can be steered in twodegrees of freedom using steering actuation elements (e.g. three or foursuch elements) terminating at the distal end of the steerable section,and a steerable section 18 b (as the deployment section) that is steeredin at least one degree of freedom to move the distal end of the shaftlaterally outward or inward in one degree of freedom using actuationelements, and which may be additionally moveable in a second degree offreedom. In another configuration, the deployment section might beconfigured to create an S-type bend. The numbers and combinations ofactively bendable and jointed articulating sections, degrees of freedom,and actuation elements can be varied from what is shown herein withoutdeviating from the scope of the present invention. Various designs forsteerable and articulating sections of instruments are known in theprior art, and so the particular details of those sections will not bediscussed here.

The motor drive 14 houses the motors whose output is used to drive theactuation elements for the steerable and/or articulating sections, asapplicable. The motor drive 14 is preferably supported within thesurgical procedure room using a support arm or alternate support.Multiple such support arms may be used to support multiple motor drives,allowing multiple ones of the system 10 to be used in a surgicalprocedure, with the surgical device shafts 16 extending through a commonincision or separate incisions. In other embodiments, the system willinclude two or more such motor drives 14, each having an associatedsurgical device 12. In such cases, a common support arm might supporttwo or more motor drives so that two or more driven surgical devices 12may extend into a patient through a common incision or through multipleincisions. In some cases, one of the surgical devices 12 might be ascope used to observe the procedure. In FIG. 3A, the motor drive 14 isshown mounted to a housing 82 that may be used to support a plurality ofsuch motor drive 14 and surgical device assemblies in positions thatallow the shafts 16 of the surgical devices to extend in parallel to oneanother through a common incision in a body cavity. One of the surgicaldevices in such an arrangement may be surgical scope that can bepositioned and oriented (including through deployment, active bending orarticulation) within the body cavity using the features describedherein. A mount 84 on the housing allows the housing to be connected toa support arm. Support arms that may be used for this purpose are knownin the art. One such arm is illustrated in US Publication No.2014/0107665. In FIG. 3A, an arm 100 is shown with a housing 82supported by it. The arm may be supported by a column that is on a basepositioned on the floor of the operating room, or it might be mounted tothe ceiling, the patient support table, or some other structure. Thisfigure shows a configuration in which four motor drives 14, each with acorresponding surgical device assembly 12, are positioned on or in thehousing 82, with the shafts 16 of the surgical devices positioned forinsertion through an incision.

Features on the housing 82, the motor drive's housing, and/or surgicaldevice assembly may be used to support the motor drive and surgicaldevice assembly in the drive relationship. For example, referring againto FIG. 3A, a support member 86 may be mounted to the housing of themotor drive 14 before or after it is covered with a sterile drape, andthe housing 44 of the surgical device 12 may be mounted to that supportmember. As described in the '098 application, the drape creates asterile barrier between the motor drive assembly 14 and the surgicaldevice assembly 12.

FIG. 4A shows the motor drive 14 with a portion its housing removed. Thesurgical device 12 is shown separated from the motor drive 14. The motordrive 14 includes motors 24 and output elements 26, which in thisembodiment take the form of pins or posts. When the motor drive 14 andsurgical device 12 are assembled, each such output element 26 is incontact with, coupled to, or engaged with a corresponding input element28 of the surgical device 12, or otherwise positioned to cause eachinput element 28 to move in accordance with its corresponding outputelement 26. The system may be set up so that the output elements 26 pushthe input elements 28 in response to motor activation, and/or so thatthe output elements pull the input elements 28. The embodimentsdescribed in this application focus primarily on “push” actuation, butit should be understood that these embodiments may be operated toinclude “pull” activation alone or in combination with push activation(as described in the '098 application), in each case without departingfrom the scope of the inventive concepts described here.

In most applications, a surgical drape will extend between the motordrive 14 and the surgical device 12, and will extend between the inputelements 28 and the output elements 26 to prevent the sterile surgicaldevice 12 from losing sterility due to direct contact with the motordevice.

In general, the motor drive 14 is configured to transfer motion frommotors 24 to linear motion of the output elements 26. For some of theoutput elements, lead screw drives 30 are used for this purpose. Thus,when a motor 24 is energized, its corresponding output element 26translates linearly towards the motor to thus pull the associated inputelement 28 of the surgical device (FIG. 1), and/or its correspondingoutput element 26 translates linearly away from the motor to thus pushthe associated input element 28 of the surgical device.

In the illustrated embodiments, each input element and its correspondingoutput element translates along a common axis, but others might usenonparallel axes, different parallel axes, or other types of offsetaxes. The interface between the output elements 26 and the inputelements 28 places the output elements 26 and input elements 28 in adrive relationship, i.e. a relationship where linear translation of theoutput elements 26 directly causes linear translation of the inputelements 28. This interface can take a variety of forms, each of whichcan be achieved without penetrating the material of the drape extendingbetween the motor drive 14 and the surgical device 12 (even though thedrape is positioned between the output elements 26 and input elements28).

The '098 application describes types of connections that can be used toallow input elements to capture, or be captured by, the correspondingoutput elements in a manner that does not compromise the drape extendingbetween them, or to engage the input elements and their correspondingoutput elements.

In the embodiment shown herein, the input elements 28 and outputelements 26 are not connected to one another, but simply push againstone another (with the drape D remaining between them, as illustratedschematically in FIG. 7). For example, the input and output elementsmight be so closely spaced that but for the drape they would betouching, or there might be a very small gap between them (with thedrape disposed within that gap),

The surgical device 12 includes a subsystem 38 that transfers the linearmotion received from the output elements 26 of the motor drive 14 to theactuation elements 42 used for steering and/or articulation of the shaftof the surgical device 12, to any other actuation elements or assembliesused for opening and/or closing the jaws of an end effector on thedistal end of the surgical device, or for axially rolling the endeffector 23. Note that rolling the end effector can be carried out byaxially rolling the shaft 16 supporting the end effector, or by rollingthe end effector relative to the shaft 16 by rotating an inner shaft(internal to the shaft 16) on which the end effector is mounted, or byother means. The linear motion received from the output elements 26 canbe transferred to the actuation elements using pivotal, linear, orrotary means (including rotary means employing pulleys).

As can be seen in the schematic of FIG. 7, each input element may beconnected by a rigid link 80 to a corresponding actuation element 42that extends within the shaft of the surgical device to an anchor point.In this embodiment, the actuation element comprises hypotube, althoughother types of element can be used. The hypotube extends along theshaft's length to its anchor point within the surgical device shaft 16,or only a proximal portion of the actuation element may be made ofhypotube with a distal portion being made of cable, wire, filament, etc.In this embodiment, activation of the motor advances output element 26,which pushes input element 28 on the other side of the drape D.

Referring to FIG. 5, subsystem 38 of the illustrated embodiment includesthe input elements 28, links 80, and actuation elements 42. Thesubsystem 38 is enclosed within a housing 44, with the input elements 28exposed through openings 46 in the housing where they can be acted uponby the output elements 26 of the motor drive 14.

Certain of the input elements 28 are each operatively associated with adifferent one of the actuation elements 42. The illustrated embodimentuses six actuation elements 42 for positioning of the end effector (e.g.4 for movement of the actively bendable section in 2 degrees of freedomand 2 for movement of the deployment section in 1 degree of freedom).Other embodiments might use as few as one actuation elements 42, whilesome might use more than six, depending on the degrees of freedomneeded, and the elements may be distributed to uniquely control degreesof freedom in any desirable way (3 elements for 2 DOF motion, 2 elementsfor 2 DOF motion (if the elements are arranged to be both activelypushed and pulled, etc.) Where the surgical device 14 is a surgicalinstrument having jaws, an additional actuation element (or, in otherembodiments, two) may be used for opening and closing of the jaws asdescribed below Referring to FIG. 8, an embodiment of the surgicaldevice 14 includes multiple sets of input elements 28. In thisembodiment, the input elements marked 28 a operate the actuationelements whose actuation results in steering of the section 18 a in twodegrees of freedom. Four such input elements, associated with fouractuation elements, are shown, but it should be appreciated that two orthree input elements and corresponding actuation elements might insteadbe used for steering in two degrees of freedom. The two input elementsmarked 28 b operate the actuation elements whose actuation results insteering of the deployment section 18 b in one degree of freedom.Additional input elements 28 b may be added if a second degree offreedom is needed at section 18 b or elsewhere along the shaft.

The input elements marked 28 c, 28 c′ are associated with opening andclosing of the jaws 23 a. These input elements are part of an actuationassembly that is anchored to a proximal part of actuation element 42 cas shown in FIGS. 12 and 13. The distal part of actuation element 42 cis not shown in the drawings, but it is operatively connected to aclevis mechanism or other system connected to the jaws to actively openor close the jaws. Such mechanisms are well known in the art.

A pivot member 40 within the housing 44 has a first end connected toinput element 28 c and a second end connected to the other input element28 c′. The pivot member 40 pivots on a center axis A, such that movementof one of the input elements 28 c, 28 c′ in one direction causes theother input element to move in the opposite direction. For example, ifone of the input elements 28 c, 28 c′ is pressed towards the housing,the pivot member 40 pushes the other input element in a direction awayfrom the housing 44. Thus, when input element 28 c is pushed (which inFIG. 13 is the direction toward the right), actuation element 42 c ispulled to the right to open or close the jaws, and input 28 c′ moves inthe opposite direction as pin 28 c. When the input element 28 c′ ispushed to the right, the pivot member 40 pushes the input element 28 cto the left, causing the actuation element 42 c to move to the left,moving the jaws to the opposite configuration (from closed to open, orfrom open to closed). Note that in some embodiments, only the input 28 cis needed. In those embodiments, the input element is actively moved(e.g. pushed) by the corresponding motor driven drive element 26 toactively open or closed the jaws as described above, but a spring 28 cis used to return the input element 28 c to its biased position once theforce imparted to it by the corresponding drive element 26 is released.

As discussed in the '098, the control system used to controlsteering/articulation/deployment/jaw actuation and roll of the surgicaldevice may receive feedback from load cells associated with each (or aplurality) of the output shafts 26 or drive pistons so as to generatesignals representing the force applied to the output shafts 26 (or drivepistons), rotary encoders that determine the rotational positions of themotors, and/or other sensors positioned to detect linear displacement ofcomponents of the drive assembly. These are also schematically depictedin FIG. 7. Signals from such sensors may be used, alone or incombination, by the control system to control movement and to thusoptimize movement accuracy.

Additional sensors may be positioned to sense the gap formed betweenoutput and input shafts 26, 28 or pistons, so as to detect whether thegap between corresponding input and output pistons is approaching apoint where an input piston might become too far out of the range of theoutput piston to be controlled by the output piston.

When the motor drive 14 and surgical instrument are placed in the driverelationship shown in FIG. 3, the input and output elements arepositioned on opposite sides of the drape as shown in FIG. 7. When amotor is energized to advance an output element axially towards itscorresponding input element, it pushes the input element towards thesurgical device housing, causing the actuation element that is coupledto that input element to be pulled.

By way of example, consider a surgical device where the actuationelements responsible for active bending of the shaft are anchored atfour locations spaced 90 degrees apart. To bend the shaft in an upwarddirection, a first motor might be energized to cause a correspondingfirst input element 28 to be pushed, resulting in the pulling of theassociated first actuation element and causing the shaft to bendupwardly. To then bend the shaft downwardly, a second motor is energizedto cause another, second, input element 28 to be pushed, resulting inthe pulling of a second actuation element anchored 180 degrees from thefirst actuation element, causing the shaft to bend downwardly. As theshaft moves between the upward and downward configurations, the firstinput element 28 moves outwardly as a result of the change in shape ofthe shaft 16, and the first motor is simultaneously energized to retractthe first output element 26 in a corresponding amount.

Other configurations using, for example, three actuation elements foractive bending of the shaft will push the appropriate combinations ofinput elements 28 to achieve the desired movement.

Note that while this application shows exemplary subsystems that may beused to perform this function, alternative subsystems can be usedwithout deviating from the scope of the invention.

The motor drive is mounted, or mountable, to a support such as a supportarm of the type used for surgical systems. Mounting may be direct or viaan intermediate structure. The surgical device is mounted to thesupport, either directly or by way of a connection to the motor drivehousing or to another structure between the surgical device and thesupport, so that the relative positions of the motor drive housing andthe surgical device (e.g. the rigid proximal portion of the shaft 16, orthe housing 44) remain fixed during the surgical procedure. Thismaintains the input and output shafts in the drive relationship throughthe procedure.

A draping system for use in covering the motor device 14 might includefeatures that accommodate the (push or pull) movement at the interfacebetween the output elements 26 and input elements 28 without tearing thedrape. Such features might include a plurality of pre-formed bellows orpockets, each positioned over one of the output elements 26, or theymight include regions of material that are more elastic than thesurrounding drape material. Alternatively, the drape can be providedwithout any such features if the elasticity of the drape is sufficientfor relative movement of the output elements without perforating thedrape. Alternative drape designs might include mechanical featuresattached to the drape to assist in the coupling of motion between outputelements 26 and the input elements 28.

Assemblies for Roll Motion of Surgical Device

It is desirable in surgery to be able to rotate the shaft of thesurgical device, or the instrument tip, relative to the longitudinalaxis of the shaft. This section describes various embodiments of linearto rotary conversion assemblies that may be used to convert linearmotion transmitted by the motor drive across the sterile barrier/drapeinto rotary motion of a feature (be it a pulley, gear, cam, belt drive,etc.) where it can be used to drive roll of the surgical device or endeffector. These embodiments allow the rotary motion to be reversible,meaning that it can be driven in both clockwise and counterclockwisedirections. In some embodiments, the rotary motion can also becontinuous.

Referring again to FIG. 8, the input elements identified as 28 d areused to effect axial rolling of the end effector 23 a. This may beachieved by rolling the shaft 16 itself, or, as illustrated, by rollingan internal shaft 17 that extends through the shaft 16 and that supportsthe end effector 23 a. Input elements 28 d are positioned on thesurgical device to interface with a central rotary component 50. Rotarycomponent 50 has a cam surface 52 formed of an externally located shelfas shown, or an internally cut cam path. In the embodiment shown, thecam surface is a continuous curved surface encircling the shaft andhaving a first apex section and a second apex section, the first apexsection being closer to the free end (the end extending in the directionof the end effector) than the second apex end. The first and second apexsections may be separated 180 degrees around the shaft as shown.

The input elements 28 d interface with the cam path/shelf such that whenone input element translates forward, it causes rotation of the rotarycomponent in one direction and forces translation of the other inputelements 28 d according to the shape of the cam surface 52. Depending onwhich input element is being actively driven (by its corresponding oneof the drive elements 26), the direction of rotation can be reversed atany time. The motion can also be continuous if the sequence in which thepins are pushed by their corresponding drive elements 26 continues inthe same direction for multiple rotations.

The interface between the input elements 28 d and the rotary component50 may also include rolling members 54 as shown in FIGS. 16 and 17.

Referring again to FIG. 1, the drive elements 26 d for driving the rollmotion extend from the motor drive housing in the circled region marked26 d. As with the other drive elements, each of these drive elements 26d is in contact with, coupled to, or engaged with a corresponding inputelement 28 d, or otherwise positioned to cause each input element 28 dto move in accordance with its corresponding output element 26 d. Themotor drive 14 may include separate drive motors for each of the driveelements 26 d, or gears may be used to allow two or more drive elementsto be driven by a common motor. In one configuration, a motor may beconfigured to drive a rotary component similar to rotary component 50,and the drive elements 26 d may be driven by the rotary component 50 ina manner similar to the way in which the input elements 28 d drive therotary component 50.

Although the drawings show the use of four input elements 28 d, threeinput elements, or more than four input elements, may instead be used.If the input elements and drive elements are configured so that thedrive elements can both push and pull the input elements 28 d, two inputelements 28 d can be used.

FIG. 18 illustrates an alternative embodiment of an assembly forconverting the linear input transferred from the drive elements 26 tothe input elements 28 into rotation for rolling the surgical device orinstrument tip. Is this embodiment, the rotation created can becontinuous and reversible, using linear translation at the drapeinterface of only two pins/pistons. This concept differs from theabove-described concept in that this concept is designed for a systemwhere the drive elements both push and pull the input elements at thedrape. Engagement between the drive elements and input elements may becarried out using overlapping mechanical features such as the hookfeatures shown in FIG. 18, or by using magnetic engagement to resistpulling apart, or other features, including those described in the '098.

The linear inputs are connected to one another in a way that they areoperating out of phase by 90 degrees. Their motion over time is depictedin the graph shown in FIG. 19. In this configuration, one input elementcan be pushed or pulled while the other is at its indeterminatelocations. This could be done with the reciprocating rack and pinionroll mechanism as described in connection with the third embodiment, orwith a simple piston/crank mechanism. This embodiment is advantageous inthat it makes use of two linear translating inputs through a drape todrive continuous and reversible roll. This would reduce the number ofrequired motors for rolling.

A third embodiment for converting the input linear translation intoaxial roll of the surgical instrument provides continuous, reversiblerotation of a shaft. It is described in the context of a system wherethe output elements only push the input elements, but it can also beused in one where both pulling and pushing are used. The mechanismconsists of a set of rack and pinions designed so that the rackreciprocates with a constant rotational input from the pinion. Thismotion can be reversed (i.e. the instantaneous direction of the rack) byreversing the pinion rotation direction. The pinion can also be drivenby the racks so that one rack/pinion set can drive a matching rackpinion set. The advantage of this system over other methods ofconverting rotational motion to linear motion is that while therack/pinion are engaged the mechanical advantage is constant. This willreduce (or eliminate) torque ripple in the rotating shaft.

Existing reciprocating rack and pinion mechanisms suffer from a problemin which, at the end of the rack travel, the pinion is (for a moment)disengaged from the rack entirely. In fact it is a requirement of thedesign that there is a moment where no gear tooth is engaged with a racktooth and the pinion rotates freely until it engages a tooth on theopposing rack. Without this clearance the mechanism would bind as therack tries to switch directions. This enables the mechanism to functionbut causes problems if there is any impediment to the rack motion at theinflection point. If the rack is not allowed to move freely (i.e. thereis some friction or a force keeping the rack from traveling freely) themechanism will jam or skip a tooth in which case it will jam the nexttime the rack reaches the end of travel.

FIGS. 20A through 20F illustrate the various states described above. Inthese drawings, the pinion P is rotating counterclockwise and the rack Ris traveling right to left.

The third embodiment makes use of a rack and pinion in the instrumentassembly for converting translational motion imparted to the rack intorotational motion of the pinion P, but modifies the rack and pinionconfiguration to overcome the difficulties described with reference toFIGS. 20A-20F. In this embodiment, in order to keep the rack 60 andpinion 62 from binding if force is applied to the rack when it isswitching directions, a secondary cam/follower arrangement is added. Oneexample of a cam/follower arrangement is shown in FIGS. 21A, 22A and22B. The arrangement can be a single cam/follower or a combination oftwo as shown. Referring to FIGS. 21A, 22A and 22B, the rack 60 includesshaped bosses 64, and the pinion 62 includes pins 66 on an arcuatemember 68 spaced apart from the teeth of the pinion 62. The pin 66 onthe pinion gear engages the boss 64 on the rack and continues to pushthe rack after the pinion gear tooth has disengaged from the rack. FIGS.21A-21D show the exemplary pin/boss configuration in the same states asdescribed with respect to FIGS. 20A-20F. In the drawings, the pinion isrotating counterclockwise and the rack is moving right to left.

FIGS. 23A and 23B illustrates rack and pinion assemblies of the typedescribed above arranged in a manner that will convert linear motion torotary motion, and that will convert rotary motion to linear motion.Three rack/pinion assembles are arranged with their pinions mounted on acommon shaft 70. Each pinion is at a different phase of its rotation, sothat its corresponding rack is at a different point along its travel asbest shown in FIG. 23A. In this specific configuration, each pinion is120 degrees out of phase with the pinion of the adjacent rack(s).

For converting rotary motion to linear motion, the shaft 70 is driven,with the rotation of the shaft 70 (and the pinions mounted to it)resulting in translation of the racks. The motor shaft used to drive theshaft 70 may be directly connected to or integral with the shaft 70, orits motion may be coupled to the shaft by gears. In this embodiment,shaft 70 has a first gear 72. The motor drives a second shaft 74 (notshown in FIGS. 23A and 23B, but see FIG. 24) that has a second gear 76connected to it.

For converting linear motion to rotary motion, application of linearforce to the pistons at one end of each of the pinions results inrotation of the shaft 70. That rotary motion can be transferred toanother shaft such as shaft 74.

FIGS. 24(a)-(f) are a sequence of photos of a prototype system showing asequence of motion of the pistons 78 of the three racks as the shaft 74is manually rotated.

The disclosed rack and pinion assemblies may be incorporated into boththe drive side to convert rotary motion into linear motion for transferacross a sterile barrier such as a drape, and/or incorporated into thesurgical device to convert linear motion received from across thesterile barrier into rotary motion that can be used to roll a part ofthe surgical device.

To incorporate the rack and pinion assemblies into the surgical systemdescribed above, a first assembly of the rack and pinion assemblies maybe disposed in the surgical device housing (like housing 4 FIG. 8), withthe pistons 78 of the racks replacing (and serving as) the inputelements 28 d of the surgical device and with shaft 74 being the deviceshaft 16 or an inner shaft that extends through the device shaft 16 andsupports the end effector.

A second assembly of the and pinion assemblies may be disposed in themotor drive, with a motor positioned to drive the shaft 70 eitherdirectly or via an intervening gear assembly as discussed above.

Note that while incorporation of the rack and pinion assemblies intoboth the drive (motor drive) side and the driven (surgical device) sideof the system is described, this is not a requirement. One embodimentmight use the rack and pinion assemblies on the surgical device side,and an alternate assembly for translating the output elements on thedrive system. As an example, each output element could be controlled bya separate motor.

Another embodiment might use the rack and pinion assemblies on the motordrive side, and an alternate assembly on the surgical device side forreceiving the linear motion and converting that linear motion to rotarymotion used to effect instrument roll.

Note also that the drawings of the third embodiment show benchprototypes and so the packaging configurations may differ once theassemblies are incorporated into the motor drive assembly and surgicaldevice of the surgical system.

Referring to the prototype systems shown in FIGS. 25 and 26, assume thatthe system 80 on the right is incorporated into the motor drive with amotor driving the shaft 74, and the system 80 a on the left isincorporated into the surgical device, with the surgical device shaft(either outer or inner shaft as discussed above) is the shaft 74 a.Surgical drape D covering the motor drive assembly is positioned betweenthe pistons of the systems 80, 80 a, and the pistons of the assembly 80a (which are the surgical device's input members for the roll function)are brought into alignment with the pistons of the assembly 80 (whichare the motor drive's output/drive members for the roll function), withthe drape D sandwiched between them as shown in FIG. 26. Note that whilethe pistons at the opposite ends of the racks (relative to the drape)are visible in the drawings, when the systems are incorporated into themotor drive assembly and the surgical device, these extra pistons neednot be exposed.

When the motor associated with shaft 74 is rotated in a first direction,the reciprocating, out of phase, motion of the three pistons of theassembly 80 produces corresponding reciprocated, out of phase, motion ofthe three pistons of the assembly 80 a, causing continuous rolling ofthe shaft 74 a. When the motor is reversed to rotate the shaft 74 in theopposite rotation, the direction of rotation of the shaft 74 a islikewise reversed.

In one implementation of the third embodiment, the motor drive isarranged to use three motors to linearly drive three output driveelements. In this implementation, the motors are configured so as todrive one output drive element (pin/piston) at a time. FIG. 29graphically depicts movement of the three output drive elements overtime, and shows how they move out of phase from one another. The blueline (1) is the path that instrument pin #1 takes. The orange, yellowand purple lines (2), (3) and (4) are paths of motor-driven pins 1, 2,and 3 respectively. The paths are plotted versus the desired roll anglein radians (x-axis). Each motor pin uses the same function, but has aphase offset of 0, 120 and 240 degrees.

The algorithm used to control the motors helps the system to avoidbinding of the rack and pinion assemblies. It can be seen at the top ofthe wave that the motor pin is caused to stop moving at a distance of1.3265 mm before the tip of the instrument pin, so as to allow the othercomponents of the instrument roll mechanism to move the pin through its“turn around” zone. Additionally, the algorithm is constructed to insurethat the instrument pin does not bind at the bottom of the wave. Forthis purpose, a 4th order polynomial (quartic) wave is added to thebottom to smoothly move the motor pin out of the way (its bottomposition is 0.25 mm below the bottom of the instrument pin trianglewave.) In order to ensure that two pins are not simultaneously pushed(an action that can cause binding), the “disengagement” point wheretransition is made from the linear section to the polynomial curve isdesigned to overlap with the other pin's “flat” area by a few degrees toensure that motor pin 3 is still stationary in its “flat” zone whenmotor pin 1 is moved away from the instrument pin. See the enlargedsection of the chart shown in FIG. 30, where a black line marks thepoint at which motor pin 1 is disengaged from the instrument pin. Thissmall amount of “dead zone” where no motor is driving a pin forwardensures that only one pin actively drives the mechanism at once. Thequartic function was designed to smoothly move the pin back to itsminimum position more quickly than could be achieved using a 2nd orderpolynomial (quadratic) curve.

It should be pointed out that while FIGS. 23A-25B show the pinions forthe racks mounted to a common shaft (where each pinion is out of phasewith the others to enable continuous rotation of the pinion shaft), inan alternative embodiment the pinions for each rack need not share acommon shaft.

FIG. 26 shows an embodiment in which each pinion 162 has its own axis(three pinions are shown. Each pinion 162 includes a spur gear 163 thatmoves integrally with the pinion. The pinions interface with one anothervia these spur gears. The manner in which the pinions 162 move withinthe racks 160 is similar to that described above.

Where the assembly is used on the driven side (as part of the surgicaldevice assembly 12), one of the pinions has a belt pulley our otheroutput assembly coupled to its rotary motion such that the belttranslates the rotation of the mechanism to the output shaft 174 for endeffector rotation. Where the assembly is used on the drive side (as partof the motor drive assembly), shaft 174 is an input shaft that receivesrotational motion from a motor, causing linear motion of the pistonsextending from the pinions, whose reciprocating pistons may thustransmit the linear motion through the drape in the manner describedabove.

It should also be noted that although the embodiments shown above usethree or more pins for effecting rotation (a configuration particularlyuseful when only pushing is being carried out between the drive pins andthe driven pins, as opposed to both pushing and pulling. While thoseembodiments can be used in systems that make use of both pushing andpulling between the drive side pins and the driven side pins, push/pullsystems can also make use of as few as two pins, which may be out ofphase with one another by 90 degrees.

A fourth embodiment of an assembly for converting linear motion torotary motion is shown in FIG. 27. This configuration may beincorporated into the surgical device so that linear motion transferredfrom output elements of the motor drive (across the drape) is receivedand converted to rotary motion for rolling the surgical device shaft.The fourth embodiment uses two parallel lead screws, spaced apart suchthat the gear molded or cut into the lead screw nuts sync. The leadscrews must be keyed so that they do not rotate. When the lead screw istranslated, it forces a rotation on its corresponding nut. The gear onthat rotating nut forces rotation of the adjacent nut in the oppositedirection. The rotation of the adjacent nut forces translation of theadjacent lead screw. Therefore, pushing one lead screw forward resultsin a reverse translation of the adjacent lead screw.

In this embodiment, the lead screw nut also has a timing belt pulleymolded or machined into its outer diameter. Rotation of that nut drivesa belt and another pulley to perform a desired action—in this case thataction is instrument rotation. This system requires a balancing oftorque and amount of rotation—which can be optimized based on the leadscrew selection and gear train ratio on the belt drive.

A fifth embodiment of an assembly for converting linear motion to rotarymotion is shown in FIG. 28. This embodiment consists of two pistons,each engaging with two half-circle bevel gear “racks”. Translating onepiston forward tilts both bevel gears in one direction and translatesthe adjacent piston in an equal and opposite direction.

The bevel gear racks are positioned to interface with a centrallylocated partial bevel gear. Gear tooth timing is crucial to thisconcept. The partial bevel gear only interfaces with one side of therack at a time. When that rack is tilted in one direction or the other,the bevel gear is rotated in a direction corresponding with the racktilt.

At the end of travel for the rack, the partial bevel gear is designed tojump to the adjacent track, such that tilting the racks back in theother direction actually results in the same direction of rotation onthe bevel gear. This enables continuous rotation of the bevel gear wherethe partial bevel gear jumps from rack to rack at the end of pistonstroke.

A sixth embodiment is similar to the FIG. 16 embodiment. It can beoperated with 3 or more pistons, equidistant (or not) and havingparallel axes (or not). Each piston interfaces with an intermediate partthat helps compensate for changes in angles in 2 directions. The partcan be shaped like a “T”, such that the primary leg of the “T” isrotationally connected to each piston. This allows the “T” part torotate in an axis that is perpendicular to the axis of the piston. Thetop part of the “T” is rotationally connected to a wobble plate suchthat it can provide an additional degree of rotation during movement.

The wobble plate toggles back and forth about a centrally located pivot.As it toggles back and forth, it interfaces with a centrally locatedshaft that has two diameters. The first diameter is the primary rotationaxis and the shelf between the first and second diameters is angledrelative to the shaft axis. The wobble plate interacts with the angledshelf such that pushing the wobble plate forces rotation on thecentrally located shaft. The rotation can be reversed by reversing thedirection of the piston movement.

This concept is used in axial engine design. In embodiments where thedrive elements are configured to both push and pull the input elements(as opposed to only pushing them), this embodiment could be modified toreduce the number of pistons to 2 pistons operating out of phase withone another (most efficient at 90 degrees out of phase).

A seventh embodiment is a slider crank embodiment which makes use of twoor more pistons, with the pistons operating out of phase with oneanother. The pistons interface with a rotary component through anintermediary linkage. The pistons may be oriented such that they haveequal and opposite translation, or they could operate out of phase suchthat their translation is not equal and opposite.

Each piston has a linkage connected at the top of the piston and theother end of each linkage is connected to a wheel (or crank).Translating a piston forward causes rotation of the wheel. Rotation ofthe wheel forces the adjacent piston to move as well.

This concept can be operated with more than two pistons and, if thedrive/output elements are configured to both push and pull the inputelements, two pistons can be used to create continuous and reversiblerotation on the wheel, assuming the two pistons operate out of phasewith one another. This allows second piston to still generate rotationwhen the first piston is at its indeterminent locations

The motor drives and surgical devices described herein are components ofa surgical system that includes a user input device used by a surgeon toinput instructions to the surgeon as to the desired movement oractuation of the surgical devices. The surgical system further includesa control system including one or more processors that receive signalsfrom the user input devices and from sensors of the system, and thatgenerate commands used to drive the motors to cause active bending,deployment, actuation, etc. of the surgical devices in accordance withthe user's input. A display for displaying an image obtained from ascope within the body cavity (e.g. a scope positioned and manipulated asdescribed herein) is typically positioned in proximity to the user inputdevice, allowing the surgeon to view the image of the procedure whiles/he operates the user input device. User input devices and controlsystems for robotic surgical systems, and laparoscopic/endoscopic imagedisplays are known to those skilled in the art and so details of suchsystems are not provided herein.

To use the system, the hospital staff positions sterile drapes over themotor drive units, with the sterile drape material extending over theoutput elements. This step may be performed with the motor drivesmounted to the support. Surgical devices are mounted to the system toposition the input elements in a drive relationship with theircorresponding output shafts, with the sterile drape disposed between theinput elements and output elements. During use of the system, thesurgeon operates the input devices while observing the procedure on thedisplay. The control system operates the motors in response to userinput so as to articulate, deploy, roll and actuate the surgicalinstruments in accordance with the user instructions.

In any of the disclosed embodiments, the motors used for driving may bereplaced with other types of drivers including, without limitation,hydraulic or pneumatic drivers. Mechanical communication is possible bymeans of hydraulic actuation transmitted across the drape, withoutpenetrating the drape.

Open Robotic Manipulator Platform and Attachable Implements

In a system of the type described in the '098, a robotic system includesa drive assembly/motor assembly 214 (which may be like motor driveassembly 14 described above) providing exposed output elements 226 suchas the pins/pistons described above having linear displacement that canbe precisely controlled. The motors 224 and the corresponding pins 226can be arranged in a variety of patterns/arrays to create an overallconfiguration of pins/pistons, including the configurations described inthe '098 as well as those shown in FIGS. 31A-31C.

A surgical robotic system of this type may provide an open platform thatcan be used for various types of instruments having functions(instrument roll, articulation in one or more degrees of freedom, jawactuation, etc) that are actuated using linear input, without requiringthat particular drive pins 226 be used to actuate a particular type offunction. In other words, a particular drive pin might actuate onefunction (e.g. shaft articulation or bending) when one surgical deviceis mounted to the motor drive assembly, yet actuate a different function(e.g. instrument roll) when a different surgical device is mounted tothat motor drive assembly. This allows creation of an array or patternof any number of motors against which instruments can be assembled overa sterile drape.

The motor array and corresponding pin arrangement may have any number ofdifferent arrangements. For the purposes of this description, the drivepins 226 are arranged in a 2×6 arrangement as shown in FIGS. 32A-32E.This may achieved by arranging the motors 224 in the rectangularconfiguration shown in FIG. 31C. As will be understood from thedescription of FIGS. 32A-32E that follows, the drive system allows asingle drive array to used with a variety of interchangeable instrumentswithout requiring that particular pins of the drive array be dedicatedto just a single surgical device function.

Referring to FIG. 32A, the illustrated circles represent drivepins/pistons 226 a, 226 b, 226 c, 226 d. In exemplary systems, each suchdrive pins may be capable of moving from 0 mm to 20 mm with the sameprecision and load. A variety of instruments can be designed aroundthese inputs to enable any number of feature sets.

For example, the pattern of FIG. 32A, below, read from left to right,describes an instrument that has six pins dedicated to articulation(pins 226 a), three pins dedicated to instrument roll (pins 226 b), andtwo pins (226 c) dedicated to jaw actuation (green). The remaining pin226 d is un-utilized for this particular instrument.

In another example shown in FIG. 32B, the first 6 pins 226 a arededicated to articulation, the next column of pins 226 b are used forinstrument roll, and the two columns of pins 226 c on the right may beused to articulate the surgical instrument's end effector or actuate awrist mechanism.

In a third example shown in FIG. 32C, the first column's two pins 226 amight enable instrument roll, while the next six pins 226 b allow forarticulation, and the final pins 226 c are not utilized for thatparticular instrument.

Still another example could be a suction/irrigation application wheremore than one surgical device may be positioned at a single motor array.Referring to FIG. 32D, as one example of such an arrangement, the sixpins 226 a of the first three columns may enable articulation as before,the pins 226 b of the next two columns are un-used, the last two pins226 c (the far right column) are used to operate a valve mechanism toswitch between three positions: (1) Off, (2) Suction Enabled and (3)Irrigation flow. In this case the valve mechanism may be removeablyattached to the articulation device, the articulation device having achannel through which fluid may pass in either direction.

All of the above examples use six pins for actuating articulation of thesurgical device. However, any number of pins could drive any number ofmechanisms to provide motion of the end effector. For example, the FIG.32E arrangement could be used for an instrument that has eight actuators(corresponding to pins 226 a) for tip positioning, two actuators(corresponding to pins 226 b) for performing roll and two actuators(corresponding to pins 226 c) for performing jaw actuation.

The above examples provide only a small subset of what is possible withthis particular motor array. Other shapes of arrays are possible,including a 3 row×4 column array, a cylindrical array as described aboveor even a non-uniform array if such a motor array were required forspace or design reasons. A motor drive using twelve actuation pins couldbe used to actuate the functions needed for both simple and complexsurgical devices, including surgical staplers and advanced energydevices.

With this type of drive system, an electromechanical surgical system canbe provided that includes a uniform motor array, in which each driver isconfigured to have the same range of travel, precision, speed and force.This enables instruments to be designed with any degree of freedomcascade desired

The following description relates to a configuration in which thesurgical device 212 is a robotically-controlled, steerable open lumeninstrument, which may have functions (e.g. bending/articulation) thatcan be driven as described in the '098 using a first subset of theavailable pins of the drive assembly, and to which other auxiliarydevices 213 can dock and have their functions actuated by the driveassembly 214 of the robotic system via a second subset of the pins ofthe drive assembly. Thus both the surgical device 2121 and auxiliarydevice can be driven or actuated via the robotic user interface, by wayof the pin actuators on a common drive assembly.

An embodiment shown in FIGS. 33A and 33B includes a surgical device 212that includes an instrument housing and shaft with a steerable distalend. Input pins 224 a of the surgical device receive linear motion fromoutput pins 226 a of the drive assembly 214 to control this steeringfunction, as described in the '098 application. The instrument shaft isan open lumen that can be used to pass fluids or catheters, surgicaltools or materials, directed to and from a desired location in thesurgical site. The instrument housing 244 and/or drive assembly frameenables docking of the auxiliary devices 213 so they can be supportedduring use.

Drive pins 226 b on the drive assembly 214 deliver motion to drive pins224 b on the auxiliary instrument in order to actuate its functions. Forexample, the auxiliary instrument 213 docked to the steerable open lumeninstrument may be a suction irrigation implement fluidly coupled to theopen lumen so that the suction irrigator can administer fluid throughthe open lumen of the open lumen, or be used to evacuate fluid from thesurgical site through the open lumen. Drive pins 226 b of the driveassembly drive pins 224 b of the suction irrigation implement, which areoperatively associated with the function of the valve system within thesuction irrigation implement 213. Thus, movement of pins 224 b actuatesthe valve system to selectively deliver/terminate administration ofirrigation fluid and/or suction based on input given to the roboticsystem by the surgeon or the surgical staff (e.g. using a surgeon inputdevices at the surgeon console).

Referring to FIG. 34, another example of an auxiliary device 213 is abiopsy tool that is passed down the shaft of the open lumen instrument.Movement of the biopsy jaws 213 a is actuated by delivering motion fromthe drive pins 226 b to the inputs 224 b as previously described, whilesteering of the shaft of instrument 212 is actuated by a differentsubset of the drive pins as discussed above.

In a modification of the FIGS. 33A and 34 embodiments, the auxiliarydevice may be a diagnostic device, such as a multispectral fiber-optictool that can be being passed down the open lumen of the instrument andsteered into place (through motion of the steerable surgical device)where the fiber-optic tool can be used to perform a tissue analysis.

The open platform robotic surgical system described here can be used toallow disposable surgical instruments to attach to a re-usable orlimited-life steerable instrument in a way that the disposableinstrument can be steered about the abdomen and actuated to performspecific surgical tasks.

While certain embodiments have been described above, it should beunderstood that these embodiments are presented by way of example, andnot limitation. It will be apparent to persons skilled in the relevantart that various changes in form and detail may be made therein withoutdeparting from the spirit and scope of the invention. This is especiallytrue in light of technology and terms within the relevant art(s) thatmay be later developed. Moreover, features of the various disclosedembodiments may be combined in various ways to produce variousadditional embodiments.

Any and all patents, patent applications and printed publicationsreferred to above, including for purposes of priority, are incorporatedherein by reference.

We claim:
 1. A method of axially rotating a surgical device in anelectromechanical surgical system comprising: providing a drive unit ona support, the drive unit comprising a plurality of actuators and aplurality of output elements, each actuator operable to linearlytranslate a corresponding one of the output elements; providing asurgical device comprising an elongate device shaft, and an inputsubsystem carried at the proximal end of the shaft, the input subsystemincluding a plurality of input elements; removably mounting the surgicaldevice relative to the support to position each output element in adrive relationship with a corresponding input element; and operating oneof the plurality of actuators to linearly translate an output element,wherein linear translation of the output element causes lineartranslation of a corresponding input element and axial rotation of theelongate device shaft.
 2. The method of claim 1, the output element andthe input element linearly translate along a common axis.
 3. The methodof claim 1, further including mechanically engaging each input elementto its corresponding output element.
 4. The method of claim 1, furtherincluding magnetically interfacing each input element with itscorresponding output element.
 5. The method of claim 1, wherein the stepof positioning each output element in a drive relationship with acorresponding input element is performed without mechanically attachingthe input element to its corresponding output element.
 6. The method ofclaim 1, further positioning a sterile drape between the input elementsand the output elements.
 7. The method of claim 6, wherein methodincludes positioning the sterile drape such that the input and outputelements do not penetrate the drape.
 8. The method of claim 1, whereinthe conversion assembly includes a shaft having a cam surface, whereintranslation of each input element against the cam surface causesrotation of the shaft, and rotation of the shaft results in rotation ofthe device shaft.
 9. The method of claim 8, wherein the cam surface isdefined by a collar on the shaft.
 10. The method of claim 8, wherein thecam surface is defined by a groove in the shaft.
 11. The method of claim8, wherein the shaft has a first end, and wherein the cam surface is acontinuous curved surface encircling the shaft and having at least twoapex sections, including a first apex section and a second apex section,the first apex section closer the first end than the second apex end.12. The method of claim 11, wherein the first and second apex sectionsare separated 180 degrees around the shaft.
 13. The method of claim 1,wherein the plurality of inputs are each operatively associated with alinear-to-rotary conversion assembly, wherein said linear-to-rotaryconversion assemble includes a shaft and plurality of rack and pinionassemblies, each rack and pinion assembly including a pinion mounted tothe shaft, and a rack that is engaged with the pinion such that lineartranslation of the rack produces rotation of the pinion and thatincludes one of the input elements, wherein each rack is positionedrelative to its corresponding pinion such that the racks move linearlyrelative to the shaft, the linear motion of each rack being out of phasewith that of the other racks such that the collective motion of theracks causes continuous rotation of the shaft, and wherein the shaft andthe device shaft arranged such that rotation of the shaft results inrotation of the device shaft.
 14. The method of claim 12, wherein eachrack and pinion assembly further includes a cam surface disposed on therack and a follower carried by the pinion, the cam surface and followershaped such that when teeth of the rack and pinion disengage duringlinear travel of the rack relative to the pinion in a first direction,contact between the cam and follower cause the relative motion of therack and pinion to continue in the first direction despite thedisengagement of the teeth.
 15. A method of using a surgical systemcomprising: providing a drive unit on a support, the drive unitcomprising a plurality of actuators and a plurality of output elements,each actuator operable to linearly translate a corresponding one of theoutput elements; providing a surgical device comprising an elongateshaft having a distal articulation section, and a plurality of firstactuation elements extending through the shaft, an input subsystemcarried at the proximal end of the shaft, the input subsystem includinga plurality of first input elements each operatively associated with acorresponding one of the first actuation elements, each first inputelement linearly translatable relative to the elongate shaft; providinga second surgical device comprising a second shaft, the second surgicalinstrument further comprising a second input subsystem carried at theproximal end of the shaft, at least one second actuation element forcausing motion of a portion of the second surgical device, the secondinput subsystem including a plurality of second input elements eachoperatively associated with a corresponding one of the second actuationelements, each second input element linearly translatable relative tothe second shaft removably mounting the surgical device mounted relativeto the drive unit to position a first plurality of output elements indrive relationships with corresponding input elements; operating anactuator to linearly translates an output element, causing lineartranslation of a corresponding input element and engagement of anactuation member; removing the surgical device from its positionrelative to the drive unit; after removing the surgical device,removably mounting the second surgical device to position a secondplurality of output elements in a drive relationship with correspondingsecond input elements, wherein the first plurality and second pluralityare not identical to one another; and operating an actuator to linearlytranslates an output element, causing linear translation of acorresponding second input element.
 16. The method of claim 15, whereinoutput elements that are positioned to actuate a first function of thefirst instrument when it is positioned to be driven by the drive unitare positioned to actuation a second, different, function of the secondinstrument when the second instrument is positioned to be driven by thedrive unit.
 17. A surgical method comprising: providing a drive unit ona support, the drive unit comprising a plurality of actuators and aplurality of output elements, each drive unit operable to linearlytranslate a corresponding one of the output elements; providing a firstsurgical device comprising an elongate tubular shaft having a distalarticulation section, and a plurality of actuation elements extendingthrough the shaft, an input subsystem carried at the proximal end of theshaft, the input subsystem including a plurality of input elements eachoperatively associated with a corresponding one of the actuationelements, each input element linearly translatable relative to theelongate shaft; providing an auxiliary device having second inputelements, each operatively associated with an actuation element for afunction of the auxiliary device, removably positioning the surgicaldevice relative to the drive unit to position a first plurality ofoutput elements in drive relationships with corresponding inputelements; operating an actuator to linearly translate an output element,causing linear translation of a corresponding input element andengagement of an actuation member; removably mounting the auxiliarydevice relative to the drive unit to position a second plurality ofoutput elements in a drive relationships with corresponding second inputelements, the first plurality different from the second plurality,operating a plurality of the plurality of actuators to simultaneouslydrive the surgical device and the auxiliary device.